What is the relation between microns and kD? I know there is a list with 0.1um/1000kD - 0.0015um/5kD. But a membrane for westernblot has a pore size of 0.45um... but proteins of 20kD are still there... is that only because the denaturation (no 3D foldings)?
What kind of factors (proteins?) can't pass a 0.2um filter in there folded form?
If I see the list of relation between micron and kD, 0.2micron must be very big and factors upto 2000-3000kD will pass... is that true or will I miss something in my reasoning?
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bob1
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Posted 28 February 2011 - 04:29 PM
No, your reasoning is perfectly sound... the micron scale is much bigger than most proteins. The reason they do not pass is that the membranes are charged and bind the protein.
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riesjart
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Posted 01 March 2011 - 07:22 AM
Ok, thank you! But the other question is still there...
We are using a normal 0.2um filter and we are expacting that all proteins will pass the filter... but we are loosing some factors for our cells. What kind of factors (proteins?) can't pass a 0.2um filter? If by a 0.1um filter will pass proteins to 1000kD, what will a 0.2um filter get out of the culture medium?
We are using a normal 0.2um filter and we are expacting that all proteins will pass the filter... but we are loosing some factors for our cells. What kind of factors (proteins?) can't pass a 0.2um filter? If by a 0.1um filter will pass proteins to 1000kD, what will a 0.2um filter get out of the culture medium?
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bob1
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Posted 01 March 2011 - 02:45 PM
Some proteins aggregate and these won't pass through filters easily. Other proteins are charged and may bind to the filter.
